Refine timeout control; refine rest book examples.

webcc/utility.h

@@ -3,11 +3,16 @@
 
 #include <iosfwd>
 #include <string>
+#include <vector>
 
 #include "boost/asio/ip/tcp.hpp"
 
 namespace webcc {
 
+// Adjust buffer size according to content length.
+// This is to avoid reading too many times.
+void AdjustBufferSize(std::size_t content_length, std::vector<char>* buffer);
+
 void PrintEndpoint(std::ostream& ostream,
                    const boost::asio::ip::tcp::endpoint& endpoint);